Non-ablative laser/light treatments, e.g., facial photo rejuvenation, are becoming an increasingly popular procedure in correcting the undesired side effects of photo and chronological aging. Non-ablative facial treatments have been shown to improve rhytides, pilosebaceous changes, pigmentary skin alterations, lentigines, and vascular lesions including facial telangiectasias and diffuse redness. These treatments are attractive to physicians and patients because of minimal or no healing time and because they reduce inconvenience and risk for a patient.
Intense Pulsed Light (IPL) devices can be used for Type-I photo rejuvenation. This includes vascular (reds) and pigmentary (brown) changes associated with photoaging, lentigens, telangiectasia and symptoms of rosacea. An advantage of the IPL is that it can reduce both vascular and pigment dyschromias with one pass (e.g., using the same treatment parameters). This leads to ease of use, simplicity and speed of operation. A KTP 532 nm laser device with 10 mm spot is also capable of treating vascular and pigmentary changes in one pass. A disadvantage of a KTP device is that it is not well-suited for hair removal and other dermatological treatments. The IPL is not well-optimized for hair removal.
Alexandrite lasers are mainly known for their ability to remove hair. Recently, it has also been used for treating pigmented lesions. Dr. Rosenbach has used the alexandrite laser to treat medium-brown solar lentigines with fluences ranging from 35 to 50 J/cm2 and a pulse duration of 5 msec (Arch. Dermatol., Vol. 138, April 2000, pp. 547-548). Dr. Mehrabi reported treatment of seborrheic keratoses using 100 J/cm2 with a spotsize of 8 mm. Dr. Mehrabi's treatment shows that using high fluence with short pulse durations results in various unwanted side effects, such as scarring and hypopigmentation complications (“Lasers for Seborrheic Keratoses,” Dermatol. Surg., Vol. 28, May 2002, pp. 437-439). Cynosure Laser Company markets an alexandrite laser for pigmented lesions and recommends using a customized short pulse mode (0.5 msec) to provide effective treatment of pigmented lesions. Candela Corporation has published several clinical papers and clinical bulletins regarding treatment of epidermnal pigmented lesions with a 3 msec pulsed alexandrite laser (e.g., the GentleLase model laser). These treatments were performed with and without DCD cooling, and used fluences as high as 40 J/cm2.
A disadvantage of using fluences less than 50 J/cm2 for treating facial epidermal pigmented lesions such as lentigines is that they are not optimal for treating vascular lesions, and therefore, using the alexandrite laser with these treatment parameters cannot be useful for a single pass non-ablative skin treatment, where vascular lesions are present.
The alexandrite laser has also been used to treat vascular lesions. Dr. Kauvar used the 755 nm, 3 msec alexandrite laser with an 8 mm spot and fluences of 60 to 80 J/cm2 to treat leg telangiectasia and reticular veins (“Pulsed Alexandrite Laser for the Treatment of Leg Telangiectasia and Reticular Veins,” Arch Dermatol, Vol. 36, November 2000, pp. 1371-1375). Although vessel clearance was good, hyperpigmentation developed in 35% of treatment sites. Dr. Eremia compared side by side 1064 nm, 810 nm, and 755 nm for the treatment of leg veins (“A Side-by-Side Comparative study of 1064 nm Nd:YAG, 810 nm Diode and 755 nm Alexandrite Lasers for Treatment of 0.3-3 mm Leg Veins,” Dernatol. Surg. 28:3 March 2002, pp. 224-230). Dr. Eremia used 3 msec pulse duration with fluences of 60-70 J/cm2 and a spot with 8 mm. Dr. Eremia claims that lower fluences do not consistently damage leg veins. Lowering the fluences below 50-60 J/cm2 drastically reduces the effectiveness for leg veins.
A disadvantage of using these pulse durations for treating vascular lesions is that, for example, they are associated with higher occurrence of side effects such as purpura and post-inflammatory hyperpigmentation. In addition, these studies examined leg veins only, and not facial vascular lesions. Therefore, using an alexandrite laser with these treatment parameters may not be useful for a single pass non-ablative skin treatment. In facial rejuvenation treatments, it is desirable to have minimum side effects.
The Arion laser device is a long-pulsed alexandrite laser system. The main area of application is laser epilation. The system is also suitable for the treatment of superficial vascular alterations. The laser can produce up to 100 J/cm2, a pulse width of 1-50 msec, and spot sizes of 3, 4, and 5 mm. The system generally uses air cooling.
There are also several patents on using the alexandrite laser for the treatment of vascular lesions, e.g., U.S. Pat. Nos. 5,749,868; 5,843,072; 6,273,883; and 6,610,052. These patents disclose methods and devices to selectively damage vascular targets and blood vessels (leg veins, telangiectasia, ecstatic blood vessels of vascular lesions, and port wine stains below the dermal/epidermal boundary), as well as other biological tissue. Fluences up to about 50 J/cm2 are reported.
A disadvantage of the methods described in these patents is that they are not optimal for treating vascular lesions. In addition, the fluences used by these methods do not lead to effective vessel closure for a vascular treatment, and the treatments do not include cooling of the skin. The 755 nm is strongly absorbed by melanin within the epidermis, and therefore epidermal cooling is important. Optimal vascular treatments cannot be performed using the best modes of operation suggested by the above patents and patent applications.
Therefore, what is needed is an improved method and apparatus based on a 755 nm alexandrite laser system, or similar wavelength device, that can perform non-ablative treatments targeting pigmentary (browns) and vascular (reds) abnormalities using a single pass of the device.